Not sure of exact total amount even with most of it growing in pure stands on 2 steep hillsides across the creek from SE corner to north hillside next to gravel driveway of parents acreage.Its rare there isnt 1 spot over the 10 acres that I wont find one within 100 ft any direction I stand.Still has to be close to 1 acre's worth if it was all condensed in 1 spot.
If the land was much flatter it would be easier to estimate the volume.I walk through the woods 2-3 times monthly even when not cutting anything,only look for ones that died recently or had broken tops from storms.Manage to get 1 or 2 yearly.
Glad I dont rely on that alone for my heat source.....That stuff is great,but it sure wouldnt be enough by itself.
They seem to prefer upland locations,a few that were in low wetter area or next to creek bank died much quicker.Shallow root systems that wont tolerate much standing water.